Systems and methods of passive body temperature management

ABSTRACT

A cooling blanket, including a wall defining a body portion, a plurality of elongated chambers positioned within the body portion, a plurality of baffles positioned within each respective elongated chamber, at least one respective port operationally connected to each respective elongated chamber, and cooling fluid positioned within each respective elongated chamber. The respective elongated chambers are respectively sized to restrict fluid flow towards the ends.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application claims priority to co-pending U.S. ProvisionalPatent Application Ser. No. 63/134317, filed Jan. 6, 2021.

BACKGROUND

The average adult human body emits over 100 watts of latent heat.Blankets are used to regulate personal body temperature by increasingthe resistance to thermal diffusion across a barrier. As heataccumulates the local body temperature increases. Passive heatingblankets, such as down comforters and wool blankets, as well as activeheating blankets, such as electric blankets and electric heating pads,are known in the art. These devices regulate a user's body temperatureby concentrating the thermal energy produced by the user, and in thecase of active blankets, adding thermal energy to the consumer throughthe use of resistive electrical elements. While blankets are efficientat increasing body temperature, few options exist for decreasing bodytemperature.

Conventional strategies for decreasing body temperatures rely ondecreasing the temperature of the entire ambient environment, oftenthrough air conditioning or open ventilation with the environment. Thismethod is highly energy inefficient where the ambient temperature of anentire room or even house is adjusted for the sake of personal cooling.In addition, environmental changes may adversely affect the comfortlevels of other individuals resting in the ambient environment.

Previous attempts to make a cooling pads or blankets have relied on opencircuit actively recirculating systems where a fluid filled pad orblanket is continuously flushed with fresh fluid provided by a fluidreservoir and pump. While these systems are effective, they are notsuitable for passive cooling applications. They also need toperiodically change the fluid in the fluid reservoir once the fluidtemperature approaches body temperatures. As a result, these systemstypically only provide transient benefits of up to a few hours.

Other attempts to make cooling blankets have focused on thermalabsorption through the use of high heat capacity acrylate gels; however,these systems are also only effective for a short period of time losetheir effectiveness once the gel approximates body temperature. Whilethe high viscosity acrylate polymers enable relatively even distributionacross the blanket, the high viscosity also limits thermal conductivityand cooling rates. In addition, polymer filled blankets must be shippedas a prefilled structure due to the sealed design and hazardous natureof poly-acrylate gels, or the like. As a result, previous attempts toutilize polymer gel filled chamber to impart cooling have achievedlimited success.

Thus, there is a need for a more efficient means for decreasing personalbody temperature regulation without the need for adjusting the ambientenvironment. The present invention addresses this need.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1. is a diagrammatic representation of a horizontal cross sectionof a first embodiment of the present invention.

FIG. 2. is a perspective view the embodiment of FIG. 1.

FIG. 3. is a diagrammatic view of a first weld patter according to asecond embodiment of the present invention.

FIG. 4. is a diagrammatic view of a second weld patter according to asecond embodiment of the present invention.

FIG. 5. is a diagrammatic view of a third weld patter according to asecond embodiment of the present invention.

FIG. 6. is a diagrammatic view of a fourth weld patter according to asecond embodiment of the present invention.

FIG. 7 schematically illustrates introducing a fluid having surfactantsand active cooling agents through a port into a cooling blanket of FIG.1.

DETAILED DESCRIPTION

Before the present methods, implementations, and systems are disclosedand described, it is to be understood that this invention is not limitedto specific synthetic methods, specific components, implementation, orto particular compositions, and as such may, of course, vary. It is alsoto be understood that the terminology used herein is for the purpose ofdescribing particular implementations only and is not intended to belimiting.

As used in the specification and the claims, the singular forms “a,”“an” and “the” include plural referents unless the context clearlydictates otherwise. Ranges may be expressed in ways including from“about” one particular value, and/or to “about” another particularvalue. When such a range is expressed, another implementation mayinclude from the one particular value and/or to the other particularvalue. Similarly, when values are expressed as approximations, forexample by use of the antecedent “about,” it will be understood that theparticular value forms another implementation. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where said event or circumstance occurs and instances where itdoes not. Similarly, “typical” or “typically” means that thesubsequently described event or circumstance often though may not occur,and that the description includes instances where said event orcircumstance occurs and instances where it does not.

A cooling blanket 10 according to one embodiment of the presentdisclosure comprises a body 35 with an internal, fluidically isolatedvolume defined by the blanket wall 20. The body 35 may form a bulkvolume 25, a series of channels 30 mechanically fixed to a predeterminedorientation, or a series of isolated chambers 15 mechanically fixed to aflexible structure (such as the wall 20). The body 35 and/or respectivechambers 15 may further include baffles 40 to regulate the movement offluids 45 between channels 30 within the chamber 15. The cooling blanket10 may also include a cooling fluid 45 (typically a cooling liquid), atleast one access port 50 to enable fluidic communication between thebody 35 and/or the respective chambers 15 and the external environment.The cooling fluid 45 may contain wetting agents or surfactants 65 and/oractive cooling agents 70. The cooling blanket 10 may also containventilation channels 85, fasteners 90, and /or covers 75.

Cooling blankets 10 may be constructed of a single layer 55 materialwhere the chamber wall 20 also defines the external contact surface, ormultiple layers 55, where a non-permeable layer is protected by anexternal fabric or material, such as nylon reinforced polyethylene,wherein a polyethylene material defines the non-permeable internalboundary of the chamber 15, and the nylon provide mechanical support andabrasion resistance to environmental surfaces during normal use. Layers55 may be formed utilizing molding processes such as blow-molding ofplastic preforms, or heat-sealing of multiple layers together to forminternal hollow cavities. While blow-molded structures are capable ofproducing seamless structures that are molded to access ports, they aretypically costly at low volumes due to the mold expense. Hot sealedstructures are preferred for low volume and multilayer construction. Hotseal seams 60 are typically formed by heating one or more layers 55 tothe plastic softening point thereby forming a multi-layer union. Theseams 60 are typically 3 mm to 6 mm wide and form a flat seal thatsurrounds the chamber walls 20 and defines the edge of the chambervolume. A three-dimension chamber 15 may then be formed by filling thechamber 15 with a fluid 45 through the access port 50.

A chamber 15 may be formed by a flexible, non-permeable material such asvinyl, polypropylene, mylar, polyester, polyethylene, such ashigh-density polyethylene (HDPE) or low-density polyethylene (LDPE), ornylon reinforced polyethylene, or the like. Multiple layers 55 may bepre-bonded together, as in the case of nylon reinforced polyethylene orpolyurethane reinforced polyethylene, to form a single film prior tosealing. To layer of multilayer film may then be layered such that theirnon-permeable surfaces are facing one another, and sealed usingconventional techniques. Non-permeable surfaces may further be modifiedby wetting agents or surface modifiers 65 (such as by conventionalsurfactants, such as alkoxylate surfactants, silicone surfactants,polysiloxanes, sulfosuccinates, polyacrylates, fluorinatedpolyacrylates, or star shaped polymers) so as to prefer to remain incertain predetermined portions of the body 35. A multilayer structuremay also contain one or more metalized layers 55 (such as aluminizedpolyester or aluminized mylar) or metal foil layers 55 (such as aluminumor copper foil) to further enhance thermal transmission and reflectinfrared radiation. In some embodiments, a metalized or metal foil layer55 is only used on one side of a multi-layer, hot sealed cooling blanket10 intended to enhance thermal transmission away from the user.

An access port 50 may be constructed of an open portion of the chamber15 left exposed during initial construction, and used to fill with afluid 45 prior to permanently sealing, or may be made of a separatemechanical structure such as a fill tube 50, which may be sealedpermanently through conventional techniques or temporarily through apinch valve or like technology, a check valve, a screw cap, or anycombination thereof. The access port 50 may be used to fill the blanket10 prior to packaging and be permanently sealed, or sealed by the enduser.

A fluid 45 may fill or partially fill a chamber 15 to further enhancethermal communication across the cooling blanket 10. The fluid 45 ispreferably a low viscosity fluid with typical viscosity of less than1,000 Centipoise (CP), more typically less than 500 CP, still moretypically less than 100 CP, yet more typically less than 50 CP, andstill more typically less than 15 CP. In one embodiment, the chamber 15may be filled with water, such as deionized water or tap water. Awetting agent or surfactant 65 as previously described may be added tothe fluid 45 to improve thermal communication or applied to the chamberwalls 20 prior to filling with a working fluid 45. The fluid 45 mayenter the chamber through access port 50. The volume of fluid 45typically added to a chamber 15 is less than the maximum chamber volume,and more typically less than 50 percent of the maximum volume, and stillmore typically less than 35 percent of the maximum chamber volume. Airis typically removed from the chamber 15 prior to filling and residualair is typically removed once the chamber 15 is sufficiently filled. Theresidual air forms a head space in the chamber 15, which is typicallyless than 10 percent of total chamber volume, more typically less than 2percent of total chamber volume, and still more typically less than 1percent of total chamber volume.

In some embodiments, the fluid 45 includes an active cooling agent 70.The active cooling agent 70 enhances cooling across the chamber 15 byundergoing a temperature dependent physical change across the chamber15. The active cooling agent 70 may be a miscible volatile chemical,such as isopropanol, butanol, or the like, selectively soluble volatilecompound, such as butane, a salt with a temperature dependentsolubility, such as calcium chloride, potassium nitrate, ammoniumnitrate, silver nitrate, cesium sulfate, sodium nitrate, potassiumchlorate, or the like, or a magnetically active fluid, such as aferrofluid. The active cooling agent 70 may be added to the fluid 45,such as water, such that it forms an undersaturated, saturated, orsupersaturated solution, depending on the anticipated environmentalconditions. In some embodiments a super saturated salt solution mayprecipitate or form concentrated solutions on a first surface anddissolve or form more dilute solutions on a second surface, such thatthermal transmission is enhanced across chamber volume.

The cover 75 may be a cleanable fabrics or film, such as cotton, bamboocloth, polyesters, percale, sateen, or flannel, expandedpolytetrafluoroethylene (PTFE), or the like. The cover 75 may be solid,woven, knit, formed, spun, or the like. The cover 75 may be waterpermeable or non-permeable, textured or smooth. The cover 75 may furtherinclude fasteners 90, such as buttons, hook and loop connectors,zippers, or the like for mechanically adhering the cover 75 to thecooling blanket 10.

The chamber 15 may form a channel 30 that may be defined as ageometrically restricted structure within the larger cooling blanket 10.Channels 30 define the fluid path within the chamber 15 and may be usedto resist the tendency for a fluid to selectively migrate away from theuser during operation. Typically channels 30 represent tubularstructures, that may be between 25 mm and 100 mm wide prior to fillingwith a fluid 45, and may traverse the length of the blanket 10. Channels30 may form interdigitated structures or may weave back and forth acrossthe blanket 10. Channels 30 are generally formed longitudinally alongthe length of the blanket 10 such that they are positioned from head totoe during use. Channels 30 may vary in width along their path, whichmay be typical with a longitudinal of 50 mm to 100 mm connected by to aparallel channel 30 via a side channel 30 of 10 mm to 50 mm. Channels 30are typically narrower towards their oppositely disposed ends.

One or more baffles 40 may be used to regulate and/or retard fluidiccommunication between one or more channels 30 within a chamber 15. Abaffle 40 may include flaps formed by additional film or fabric,semipermeable plugs, such as nitrocellulose or polyester fabrics, orvalves, such as check valves formed by weights, balls, needle valves,access ports, or the like. Baffles 40 may also be formed by capillarychannels of less than 25 mm wide.

The cooling blanket 10 may also contain non-movable weights 95 made of adense material, such as lead, tin, aluminum, or iron, that may be boundinto the blanket structure to provide greater mechanical stability byproviding a constant force on the user during fluidic shifts, which mayhelp to keep the blanket stationary as the user tosses and turnsthroughout the night.

Air-filled bladders 80 may be added to the blanket 10 and maintainedfluidically isolated from fluid filled channels 30 to enhance mechanicalrigidity along the air-filled bladder 80. Air bladders 80 may also beused to decrease or modulate the relative cooling efficacy along theblanket 10 and allow for greater comfort. In one embodiment, airbladders 80 are positioned within the blanket 10 in thermalcommunication with the user's arms and legs to prevent over-cooling ofthe user's extremities.

A ventilation hole 85 may be formed by removing excess film formedbeyond the hot seal seam 60 during manufacturing; these holes 85 enabledirect ambient communication across the sides of the cooling blanket 10to prevent body moisture accumulation and suffocation during use. Insome embodiments, ventilation holes 85 may be small (for example 3 mm to10 mm across their longest axis) or large (for example 100 mm to 500 mmacross their longest axis).

In another embodiment, the body 35 may form a bulk volume 25, furtherincluding a series of point welds 100 mechanically fixed to either sideof the body 35, thereby constricting the body's 35 volumetric expansion.The welds 100 may be solid or rings with hollow centers. The rings maybe sonically welded. They may be 5 to 25 mm in diameter, and for hollowrings, may have a weld thickness of at least 5 mm, more typically atleast 8 mm, more typically at least 10 mm thick. The chamber 15 may beconstructed of poly urethane of at least 60 durometer, more typically atleast 70 durometer, and still more typically 80 durometer. Welds 100 ofthe present embodiment may form an array ranging between 25 to 250 mmapart. The weld pattern 105 may be more constricted on the sides of theblanket 10 resulting in hydrostatic pressure to urge fluids 45 towardpredetermined portions of the body portion 35 of the blanket 10,typically such so as to keep the fluid 45 elevated above the user.Typically, a low viscosity fluid will drain to the sides of theindividual, thereby decreasing cooling efficiency and capacity. Byrestricting the volumetric expansion of the chamber 15, a hydrostaticpressure is produced due to the elasticity of the chamber walls 20,resulting in fluid elevation and fluid concentration at higherelevations. Examples of weld patterns may be found in FIGS. 3-6.

In other embodiment, each respective individual chamber 15 may havewelds 100 operationally connected thereto to restrict expansion.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments of particular inventions.Certain features that are described in this specification in the contextof separate embodiments may also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment may also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination may in some cases be excised from thecombination, and the claimed combination may be directed tonigh-infinite subcombinations or variations of a subcombination.

We claim:
 1. A cooling blanket, comprising: a wall defining a bodyportion; a plurality of elongated chambers positioned within the bodyportion; a plurality of baffles positioned within each respectiveelongated chamber; at least one respective port operationally connectedto each respective elongated chamber; and cooling fluid positionedwithin each respective elongated chamber; wherein the respectiveelongated chambers are respectively sized to restrict fluid flow towardsthe ends.
 2. The cooling blanket of claim 1 and further comprising aplurality of fasteners connected to the body portion and a coverconnected to the fasteners.
 3. The cooling blanket of claim 1 whereinthe fluid further comprises one of the group consisting of surfactants,wetting agents, active cooling agents, and combinations thereof.
 4. Thecooling blanket of claim 1 wherein the wall is a multilayer material. 5.The cooling blanket of claim 4 wherein the multilayer material includesa metallized layer for reflecting infrared radiation away from theblanket.
 6. The cooling blanket of claim 1 and further comprising atleast one air bladder positioned within the body portion.
 7. The coolingblanket of claim 6 wherein respective air bladders are positioned withinrespective elongated chambers.
 8. The cooling blanket of claim 1 whereinthe wall is at least partially coated with a wetting agent.
 9. Thecooling blanket of claim 8 wherein the wall is selectively coated withthe wetting agent to encourage the fluid to prefer predeterminedportions of the body portion.
 10. The cooling blanket of claim 1 andfurther comprising a plurality of welds operationally connected to thebody portion and positioned to restrict volumetric expansion of the bodyportion to generate hydrostatic pressure to urge fluid to predeterminedportions of the body portion.
 11. A thermal reduction blanket,comprising: a flexible body portion separating an interior volume froman exterior environment; a plurality of welds formed on the flexiblebody portion for restricting volumetric expansion of the interiorvolume; a liquid at least partially filling the interior volume; aplurality of baffles positioned withing the interior volume; and awetting agent at least partially covering the flexible body portion inthe interior volume; wherein the plurality of welds and the wettingagent establish a hydrostatic pressure to urge the liquid towardpredetermined portions of the flexible body portion.
 12. The thermalreduction blanket of claim 11 wherein the plurality of welds areoriented to define a predetermined pattern.
 13. The thermal reductionblanket of claim 11 and further comprising weights disposed within theinterior volume.
 14. The thermal reduction blanket of claim 11 andfurther comprising a plurality of air bladders positioned within theinterior volume.
 15. The thermal reduction blanket of claim 11 andfurther comprising a plurality of channels disposed within the interiorvolume.
 16. The thermal reduction blanket of claim 11 and furthercomprising a plurality of ventilation passages formed through thethermal reduction blanket.